Compositions providing for sustained release of an active pharmaceutical ingredient (active) are generally made by applying various layers containing said active over inert core, whereas the penetration of gastric or intestinal fluid through those layers dictates the kinetics of release or alternatively by incorporating the active into a core, for example into a tablet whereas the kinetics of release is dictated by slow disintegration/dissolution of said tablet.
Such core must according to EP 1629834 A1 contain a combination of more than one excipients. It is postulated that pellets prepared only with microcrystalline cellulose and tolterodine are insufficiently strong and also provide an insufficiently controlled release of the active substance tolterodine
The present invention is aimed at preparation of a simple immediate release pharmaceutical composition (e.g. tablets), which can be administered more than once a day, but also a preparation of a sustained release composition, by applying to said immediate release composition preferably only one coating layer which provides for sustained release.
If desired, an additional layer may be applied as anti-tacking, protective or cosmetic coat, e.g. if the composition is to be uses in sprinkle capsules, to be sprayed onto food, an additional taste masking layer may be advantageous.